Summary: Flash memory is not the same as the type of memory used as your system RAM. They have different characteristics and they're accessed differently.
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Can I use a USB RAM stick to increase system memory? |
No.
That was simple. But to avoid this becoming the shortest Ask Leo! article ever, let me explain why.
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As you can probably guess by now, all memory is not created equal. Your system memory typically resides on your computer's motherboard, and uses a very high speed interface to connect to your computer's CPU. In fact, as fast as that interface is, it's still not as fast as we would like it (so true about so many things), and most modern CPUs actually copy or "cache" blocks of memory internally where they can access it even faster.
One of the characteristics of system memory is that when you remove power, *poof*, the memory has lost whatever it contained. Time to reboot.
USB Memory Sticks, on the other hand, are expected to retain whatever you put in them when the power is removed. Heck, they're expected to retain their memory when they're completely removed from the computer. As a result they use a different memory technology typically called "flash ram", which does exactly that. It's called "flash" because the memory contents are loaded, and then a special signal is sent that, in a sense, tells the memory to "remember this, now". It's kind of like taking a picture with a flash on your camera ... the picture "remembers" the state of everything when the flash went off. Flash BIOS is called that for the same reason - it's just flash memory that contains your computer's BIOS.
The downside to flash RAM is that it's slower. Reading flash memory is slower, and writing to flash memory is MUCH slower. It works fine as a virtual disk drive because our expectations for a disk's speed are quite different than what we expect for system memory.
In addition to the issue of the memory's own speed, there's also the USB interface to consider. As fast as it is for other purposes, it, too, is significantly slower than your system's main memory.
So USB RAM sticks, memory sticks, key chain drives, geek sticks, whatever you call them, are great for portable data storage. But increasing your system's memory is an entirely different proposition.
Related:
Will my system be faster if I make my C: drive a flash drive? USB Flash drives are useful for many things, but not for running your system from them long term. We'll look at why, and a Windows Vista alternative.
How do I find out how much RAM is being used? Process Explorer is a useful way of determining how much RAM in your system is actually being used.
What is Virtual Memory? Virtual memory is conceptually somewhere between RAM and hard disk space; it's disk space used to maximize the amount of RAM available to programs.
How do I install my new USB device? Some USB devices simply require you plug it in to use them, but reviewing documentation that came with the device before you do is important.
Article C2327 - April 9, 2005
From Micosoft:
Posted by: Ken Gettys at November 9, 2008 2:31 PM"Windows ReadyBoost improves system memory and boosts performance. The flash memory device serves as an additional memory cache—that is, memory that the computer can access much more quickly than it can access data on the hard drive. Windows ReadyBoost relies on the intelligent memory management of Windows SuperFetch and can significantly improve system responsiveness."
After installing the 1GB USB flash stick (it is not ram) and setting up my Vista computer to use 350 mb of it as Memory Cache (again, not ram), I went to the Task Manager (via Ctl/Alt/Del) then to the "Performance" tab then to the "Resource Monitor" Button, then to the "Disk" Frame where I found that the "f:\ReadyBoost" drive\program had used 3,100,000 Read B/Min and 7,400,000 Write B/Min. This while I was only downloading Vista SP1 (large update) and IE 8 Beta for Vista (smaller update). Hard to tell if the 27 ms access time makes any over all difference as there were lots of small sized Page File disk references too. Closer monitoring (which I don't have time for right now) of this information may prove that using the Vista included Readyboost program and a flash drive might make a difference in providing faster accessable disk cache than hard disk page file access. While at breakfast at McDonalds I saw in a Target ad this morning for a 16gb flash stick for $49.xx which got me to think and then Google "USB Ram" to find another always friendly and often very helpful "Ask-Leo"'s blog!
Posted by: Ken Gettys at November 9, 2008 3:24 PMLeo
I understand what you say about the flash drive, statement by statement. But yourself point out that we consider the flash drive fast because for practical purposes its speed is comparable with that of a HD - and Windows has (always ? certainly for a long time) provided a way of assigning 'virtual memory', which must involve the HD spinning (spinning more). So it seems to me that in terms both of functionality, and of risk associated with increased wear and tear, the situation is much less absolute than you're painting it ?
People are asking if flash memory can be used as system RAM. The answer is an absolute no.
People have wondered if flash memory could be used for Virtual Memory. In my opinion the answer is, once again, absolutely no, since that will cause the flash memory to wear out very quickly.
Window's Vista's "ReadyBoost" is a compromise - it's not RAM, and it's not VM, but it is flash memory used in a semi-intelligent manner to boost overall performance.
07-Dec-2008
Leo,
As a real world example, I overcame a problem with multi-track recording. The program needed access to my .wav file on the hard disk - at the same time it needed to write the live audio I was recording. There were skips and stutters as I recorded. To solve this problem, I simply moved my source audio .wav file, 60 Megabytes, to a 1 Gig USB key. Then reimported the .wav file from the USB key. This freed my hard disk from having to read and write simultaneously and the skipping stopped.
I am also using this technique to create overflow cache space for After Effects and Photoshop. The access speed is not as fast as RAM, as you say, but it is fast enough for caching current work and preview data.
27-Dec-2008
i have create a ramdisk as a removable drive(Media type--3). i want to use it as a readyboost. i have edited the registry key under EmdMgt and then restart the service readyboost. but the ramdisk was not configured as readyboost. if i do same for a flashdrve it works. manually it is possible to create readyboost in ramdisk by opening the property of ramdisk.please help me if it is possible to configure ramdisk as a readyboost by program.
Posted by: Shohug at January 15, 2009 3:44 AMHI leo ! i just need to know that How can i use my 512MB or 1GB flash drive as a RAM ? please answer me on my mail ?
06-Feb-2009
Hi Leo,
Thank you for your advice. I was about to go to the store to buy a USB stick to use as RAM after a widget I just downloaded is showing I'm using about 70-80% on average.
I was always reluctant to use USB devices for ayatem memory, but the price difference ($10 for the stick opposed to $50 for the 512MB of SDRAM) . Now my inner cheapskate is asking for a solution. How effective is virtual memory from the hard drive for being used as system memory and is there a cheap alternative method to getting more system memory?
Posted by: Leo (how ironic) at February 15, 2009 4:01 AMHi! Thank you for taking the time to help me but i have a memory stick that goes inside my desktop tower...how do i find out what kind and size it is? It has a few really long numbers on it...is there a search engine that i can put one of the numbers(maybe one is a serial number) in and it comes back with type and speed? I hope u could give me pointers to locate the answer.
Posted by: Jenny Thompson at August 16, 2009 2:39 AMWell, you can use USB stick for performance enhancement. I am using a software EBoostr, which layers between Harddish and RAM.
Copies contents from harddisk and saving them in USB and later providing the data to RAM. Dont know about others, but I am quite a fan and using my 4 GB USB.
Try it, i hope you find it too useful and CHEAP.
Posted by: Janib Soomro at August 18, 2009 11:45 PMU can use USB pendrive as RAM in Windows Vista & Windows 7. Read the full detailed explantion with screenshot on the link shown here
http://jeshmal4u.blogspot.com/2009/11/usb-pendrive-alternative-for-ram-in.html
06-Nov-2009
Posted by: Rajesh Perumal at November 5, 2009 2:22 PM